U.S. soybean futures fell to their lowest level of the year Friday as mounting economic woes continued to fuel selling across asset classes.

Soybeans for November delivery, the most actively traded contract, dropped 25 cents, or 1.9%, to $12.58 a bushel at the Chicago Board of Trade. Corn futures also extended recent losses, with the December contract sliding 11 1/2 cents, or 1.8%, to a near three-month low of $6.38 1/2 a bushel.

Driving prices lower was widespread liquidation in equity and commodity markets that's stoked investor fears of an economic slowdown. The selling extended sharp losses from Thursday, when soybeans sank 2.8% and corn lost 5.2%. Soybean futures have retreated 13% since the nearby contract reached a three-year high in late August on concerns about low inventories, while corn is down 20% from an all-time high in June.

"There has been a huge amount of liquidation over the last few weeks, but there may be more to come," said Doug Bergman, broker for MF Global in Chicago.

Wheat futures avoided the selloff, rebounding from Thursday's 4.9% drop. Wheat markets felt some support from concerns about dryness reducing output in the U.S., Argentina and Ukraine.

Soft red winter wheat for December delivery rose 7 cents, or 1.1%, to $6.40 3/4 a bushel at the CBOT. Hard red winter wheat for December delivery gained 10 1/4 cents, or 1.4%, to $7.31 1/4 a bushel at the Kansas City Board of Trade. Hard red spring wheat for December delivery surged 31 cents, or 3.8%, to $8.51 a bushel at MGEX in Minneapolis.

Other markets

November rice dropped 1.1% to $16.48 1/2 per hundredweight. December soymeal slid 1.5% to $330.10 per short ton, and December soyoil sank 2.4% to 52.64c/pound. Ethanol for October delivery shed 1.4% to $2.52 per gallon. December oats fell 1.6% to a near seven-week low of $3.31 1/2 a bushel.